Processes for making ethersuccinylated hydroxyl polymers

ABSTRACT

Processes for making ethersuccinylated hydroxyl polymers are provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 11/411,334 filed Apr. 26, 2006 now U.S. Pat. No. 7,772,391, whichclaims the benefit of U.S. Provisional Application No. 60/691,104 filedJun. 16, 2005.

FIELD OF THE INVENTION

The present invention relates to ethersuccinylated hydroxyl polymers,processes for making ethersuccinylated hydroxyl polymers, and uses ofethersuccinylated hydroxyl polymers. Such uses include polymer solutionswherein the polymer solutions comprise an ethersuccinylated hydroxylpolymer; polymeric structures made from such polymer solutions; andprocesses/methods related thereto.

BACKGROUND OF THE INVENTION

Covalently attaching substituents to hydroxyl polymers, for examplehydroxyethyl, hydroxypropyl, and methyl, is well known as a way tomodify various properties of the hydroxyl polymer including solubility,viscosity, film formation, suspension of solids, and adhesiveness.Substituents which have carboxyl groups, for example carboxymethyl, canhave additional properties including emulsion stabilization, binding ofcationic species, crystal growth inhibition, and increasing thecompatibility with other polymers. The carboxyl group can also be usedto crosslink the hydroxyl polymer either by formation of ester links orby ionic crosslinks between carboxyl groups. Such crosslinked hydroxylpolymers can swell rapidly in water to form strong hydrogels.Substituents which are linked to the hydroxyl polymer via an etherlinkage, for example carboxymethyl, hydroxyethyl, hydroxypropyl, andmethyl are advantageous since the ether linkage is stable under bothacidic and basic pH conditions. Ethersuccinate is a substituent whichcontains both carboxyl groups and an ether linkage to the hydroxylpolymer.

Synthesis of substituted hydroxyl polymers can be problematic. Forexample synthesis of carboxymethyl starch in the granular form requireseither a high content of salt in the reaction mixture or the use ofsolvents in combination with water. The salt, solvents, and unreactedchloroacetate must be removed for many applications. In the case ofhydroxyethyl starch, the reactor must have expensive safety controls dueto the toxicity and flammability of the ethylene oxide reactant.

Accordingly, there is a need for substituted hydroxyl polymers which canbe made with simple, inexpensive processes and which exhibit the variousproperties of substituted hydroxyl polymers, especially the property ofbeing polymer processed in order to make various polymeric structuressuch as fibers, films, foams, and coatings.

SUMMARY OF THE INVENTION

The present invention fulfills the needs described above by providing anethersuccinylated hydroxyl polymer, processes for makingethersuccinylated hydroxyl polymers, and products and uses of suchethersuccinylated hydroxyl polymers.

In one example of the present invention, a hydroxyl polymer comprisingan ethersuccinate moiety having the formula:

wherein R¹, R² and R³ are independently selected from H, branched orlinear C₁-C₄ alkyl and mixtures thereof; R⁴ is a (CH₂)_(y); M isindependently selected from H, cations and mixtures thereof; x isgreater than 0 but less than or equal to 1; y is 0 or 1, is provided.

In another example of the present invention, a polymer solutioncomprising: a) an ethersuccinylated hydroxyl polymer according to thepresent invention; and b) a crosslinking system capable of crosslinkingthe ethersuccinylated hydroxyl polymer, is provided.

In even another example of the present invention, a polymeric structure,such as a fiber, film, foam and/or coating, comprising anethersuccinylated hydroxyl polymer according to the present invention,is provided.

In still another example of the present invention, a fibrous structurecomprising a polymeric structure according to the present invention, isprovided.

In yet another example of the present invention, a single- or multi-plysanitary tissue product comprising a polymeric structure and/or fibrousstructure according to the present invention, is provided.

In even still another example, a process for making an ethersuccinylatedhydroxyl polymer wherein the process comprises the step of reacting aprecursor hydroxyl polymer with an α, β-unsaturated dicarboxylic acid orsalt thereof to produce the ethersuccinylated hydroxyl polymer, isprovided.

In still yet another example of the present invention, a process formaking a polymeric structure according to the present invention, whereinthe process comprises the steps of:

a. making a polymer solution comprising:

-   -   i. an ethersuccinylated hydroxyl polymer according to the        present invention; and    -   ii. a crosslinking system capable of crosslinking the polymer;        and

b. polymer processing the polymer solution to produce a polymericstructure, is provided.

Accordingly, the present invention provides an ethersuccinylatedhydroxyl polymer, a polymer solution comprising such ethersuccinylatedhydroxyl polymer, a polymeric structure produced from such polymersolution and processes for making same.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic side view of a barrel of a twin screw extrudersuitable for use in the present invention.

FIG. 1B is a schematic side view of a screw and mixing elementconfiguration suitable for use in the barrel of FIG. 1A.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

“Ethersuccinylated hydroxyl polymer” as used herein means a hydroxylpolymer that comprises at least one ethersuccinate moiety. Theethersuccinate moiety may be covalently bonded directly to a carbon atomwithin the backbone of the hydroxyl polymer.

“Polymer structure” as used herein means any single physical structureproduced by an ethersuccinylated hydroxyl polymer or polymer solutioncomprising at least one ethersuccinylated hydroxyl polymer. The polymerstructures are produced from an ethersuccinylated hydroxyl polymer or anethersuccinylated-containing polymer solution that is polymer processedinto the physical structure. The polymer structures may be dry spunand/or solvent spun. “Dry spinning”, “dry spun” and/or “solventspinning”, “solvent spun” as used herein unlike wet spinning means thatpolymer structures are not spun into a coagulating bath.

The polymer structures of the present invention, especially fibers ofthe present invention, may be produced by crosslinking ethersuccinylatedhydroxyl polymers together, alone or to other polymers. Nonlimitingexamples of a suitable crosslinking system for achieving crosslinkingcomprises a crosslinking agent and optionally a crosslinkingfacilitator, wherein the ethersuccinylated hydroxyl polymer iscrosslinked by the crosslinking agent.

A “fibrous structure” as used herein means a single web structure thatcomprises at least one fiber. For example, a fibrous structure of thepresent invention may comprise one or more fibers, wherein at least oneof the fibers comprises an ethersuccinylated hydroxyl polymer structurein fiber form. In another example, a fibrous structure of the presentinvention may comprise a plurality of fibers, wherein at least one(sometimes a majority, even all) of the fibers comprises anethersuccinylated hydroxyl polymer structure in fiber form. The fibrousstructures of the present invention may be layered such that one layerof the fibrous structure may comprise a different composition of fibersand/or materials from another layer of the same fibrous structure.

The polymer structures in fiber, fibrous structure, film and/or foamform may be incorporated into sanitary tissue products and/or otherpaper-like products, such as writing papers, cores, such as tissueproduct cores, packaging films, and packaging peanuts.

One or more polymer structures of the present invention may beincorporated into a multi-polymer structure product.

“Sanitary tissue product” as used includes but is not limited to awiping implement for post-urinary and post-bowel movement cleaning(toilet tissue), for otorhinolaryngological discharges (facial tissue),and multi-functional absorbent, cleaning uses (absorbent towels), wipes,feminine care products and diapers.

“Ply” or “Plies” as used herein means a single fibrous structureoptionally to be disposed in a substantially contiguous, face-to-facerelationship with other plies, forming a multi-ply sanitary tissueproduct. It is also contemplated that a single fibrous structure caneffectively form two “plies” or multiple “plies”, for example, by beingfolded on itself. Ply or plies can also exist as films or other polymerstructures.

One or more layers may be present in a single ply. For example, two ormore layers of different compositions may form a single ply. In otherwords, the two or more layers are substantially or completely incapableof being physically separated from each other without substantiallydamaging the ply.

“Fiber” as used herein means a slender, thin, and highly flexible objecthaving a major axis which is very long, compared to the fiber's twomutually-orthogonal axes that are perpendicular to the major axis. Inone example, an aspect ratio of the major's axis length to an equivalentdiameter of the fiber's cross-section perpendicular to the major axis isgreater than 100/1, more specifically greater than 500/1, and still morespecifically greater than 1000/1, and even more specifically, greaterthan 5000/1.

The fibers of the present invention may be continuous or substantiallycontinuous. A fiber is continuous if it extends 100% of the MD length ofthe fibrous structure and/or fibrous structure and/or sanitary tissueproduct made therefrom. In one embodiment, a fiber is substantiallycontinuous if it extends greater than about 30% and/or greater thanabout 50% and/or greater than about 70% of the MD length of the fibrousstructure and/or sanitary tissue product made therefrom.

The fiber can have a fiber diameter as determined by the Fiber DiameterTest Method described herein of less than about 50 microns and/or lessthan about 20 microns and/or less than about 10 microns and/or less thanabout 8 microns and/or less than about 6 microns.

The fibers may include melt spun fibers, dry spun fibers and/or spunbondfibers, staple fibers, hollow fibers, shaped fibers, such as multi-lobalfibers and multicomponent fibers, especially bicomponent fibers. Themulticomponent fibers, especially bicomponent fibers, may be in aside-by-side, sheath-core, segmented pie, ribbon, islands-in-the-seaconfiguration, or any combination thereof. The sheath may be continuousor non-continuous around the core. The ratio of the weight of the sheathto the core can be from about 5:95 to about 95:5. The fibers of thepresent invention may have different geometries that include round,elliptical, star shaped, rectangular, and other various eccentricities.

“Weight average molecular weight” as used herein means the weightaverage molecular weight as determined using gel permeationchromatography according to the protocol found in Colloids and SurfacesA. Physico Chemical & Engineering Aspects, Vol. 162, 2000, pg. 107-121.

“Capillary Number” as used herein is a number representing the ratio ofthe viscous fluid forces to surface tension forces. Near the exit of acapillary die, if the viscous forces are not significantly larger thanthe surface tension forces, the fluid filament will break into droplets,which is commonly termed “atomization.” The Capillary Number iscalculated according to the following equation:Ca=(η_(s) ·Q)/(π·r ²·σ)where η_(s) is the shear viscosity in Pascal·seconds measured at a shearrate of 3000 s⁻¹; Q is the volumetric fluid flow rate through capillarydie in m³/s; r is the radius of the capillary die in meters (fornon-circular orifices, the equivalent diameter/radius can be used); andσ is the surface tension of the fluid in Newtons per meter.Ethersuccinylated Hydroxyl Polymers

“Hydroxyl polymer” as used herein includes any hydroxyl-containingpolymer that can be incorporated into a polymer structure of the presentinvention, such as into a polymer structure in the form of a fiber. Inone example, the hydroxyl polymers in accordance with the presentinvention are a) capable of being at least partially solubilized orswelled in water in order that they can undergo reaction with thebutanedioic acid reactant and/or b) stable to the alkaline reactioncondition.

In one example, the precursor hydroxyl polymer and/or ethersuccinylatedhydroxyl polymer of the present invention includes greater than 10%and/or greater than 20% and/or greater than 25% by weight hydroxylmoieties.

Nonlimiting examples of hydroxyl polymers in accordance with the presentinvention include polyols, such as polyvinyl alcohol, polyvinyl alcoholderivatives, polyvinyl alcohol copolymers, starch, starch derivatives,chitosan, chitosan derivatives, cellulose, cellulose derivatives such ascellulose ether and ester derivatives, gums, arabinans, galactans,galactomannans, proteins and various other polysaccharides and mixturesthereof.

Classes of hydroxyl polymers are defined by the hydroxyl polymerbackbone. For example polyvinyl alcohol and polyvinyl alcoholderivatives and polyvinyl alcohol copolymers are in the class ofpolyvinyl alcohol hydroxyl polymers whereas starch and starchderivatives are in the class of starch hydroxyl polymers.

The hydroxyl polymer may have a weight average molecular weight of fromabout 2,500 g/mol and/or from about 10,000 to about 40,000,000 g/mol.Higher and lower molecular weight hydroxyl polymers may be used incombination with hydroxyl polymers having the preferred weight averagemolecular weight.

Well known modifications of hydroxyl polymer, such as natural starches,include chemical modifications and/or enzymatic modifications. Forexample, the natural starch can be acid-thinned, hydroxy-ethylated,hydroxy-propylated, and/or oxidized. In addition, the hydroxyl polymermay comprise dent corn starch hydroxyl polymer.

Polyvinyl alcohols herein can be copolymerized with other monomers tomodify its properties. A wide range of monomers has been successfullygrafted to polyvinyl alcohol. Nonlimiting examples of such monomersinclude vinyl acetate, styrene, acrylamide, acrylic acid, 2-hydroxyethylmethacrylate, acrylonitrile, 1,3-butadiene, methyl methacrylate,methacrylic acid, vinylidene chloride, vinyl chloride, vinyl amine and avariety of acrylate esters.

The ethersuccinate moiety may be substituted on any of the hydroxylgroups present in the hydroxyl polymer to result in theethersuccinylated hydroxyl polymer. For example, the ethersuccinatemoiety may be substituted on the most acidic and/or least stericallyhindered hydroxyl groups. Preferential substitution may be occurring onthe hydroxyl attached to the carbon adjacent to the glucoside carbon.

In one example, the percentage of hydroxyls substituted withethersuccinate moieties may range from 0.1% to 99%.

In another example, the hydroxyl polymer may have other substituents, inaddition to the ethersuccinate moiety.

In yet another example, the hydroxyl polymer may comprise apolysaccharide.

A. Starch Hydroxyl Polymers

Precursor natural starch and/or modified starch-based polymer and/oroligomer materials, modified amylose (represented by Structure I below)and/or modified amylopectin (represented by Structure II below) both ofwhich are described in Kirk-Othmer's Encyclopedia of Chemical Technology4^(th) Edition, Vol. 22, pp. 701-703, starch, generally, is described atpp. 699-719, which are suitable for use as the hydroxyl polymers of thepresent invention can be characterized by the following generalstructures, alone or in combination:

wherein each R is selected from the group consisting of R_(a), R_(c),and R_(p);wherein:

each R_(a) is independently selected from the group consisting of H andC₁-C₄ alkyl;

each R_(c) is

-   -   wherein M is a suitable cation selected from the group        consisting of H⁺, Na⁺, K⁺, 1/2Ca²⁺, 1/2Mg²⁺, barium, zinc and        lanthanum (III), or ⁺NH_(j)R_(k) wherein j and k are        independently from 0 to 4 and wherein j+k is 4 and R in this        formula is any moiety capable of forming a cation, such as        methyl and/or ethyl group or derivative;

each R_(p) is

each R_(H) is independently selected from the group consisting of R_(a)and R_(c)

each x is from 1 to about 5;

n is a number that results in the polymer having a weight averagemolecular weight in accordance with the present invention.

In one example, the precursor starch hydroxyl polymer unsubstituted andthus R equals H in Structures I and II. After the ethersuccinylationreaction is carried out on the precursor starch hydroxyl polymer, R isselected from the group consisting of R_(a), R_(c), R_(p), and R_(E);

wherein:

each R_(E) is

and

each R_(H) is independently selected from the group consisting of R_(a),R_(c), and R_(E).

The “Degree of Substitution” (“DS”) for group R_(E), which is sometimesabbreviated herein “DS_(E)”, means the number of moles of group R_(E)components that are substituted per anhydrous glucose unit, wherein ananhydrous glucose unit is a six membered ring as shown in the repeatingunit of the general structure above.

The “Degree of Substitution” for group R_(c), which is sometimesabbreviated herein “DS_(c)”, means the number of moles of group R_(c)components that are substituted per anhydrous D-glucose unit, wherein ananhydrous D-glucose unit is a six membered ring as shown in therepeating unit of the general structures above.

A natural starch can be modified chemically or enzymatically, as wellknown in the art. For example, the natural starch can be acid-thinned,hydroxy-ethylated or hydroxy-propylated or oxidized. Though all starchesare potentially useful herein, the present invention can be beneficiallypracticed with high amylose natural starches (starches that containgreater than 25% and/or greater than 50% and/or greater than 65% and/orgreater than 70% and/or about 85% amylose) derived from agriculturalsources, which offer the advantages of providing polymeric structureswith superior material properties as compared to starches containinglower amounts of amylose. In order to form melt compositions of highamylose starches to make polymeric structures, it is usually necessaryto substitute the starch and ethersuccinate is an effective substitutionto enable melt compositions.

Chemical modifications of starch typically include acid or alkalihydrolysis and oxidative chain scission to reduce molecular weight andmolecular weight distribution. Suitable compounds for chemicalmodification of starch include organic acids such as citric acid, aceticacid, glycolic acid, and adipic acid; inorganic acids such ashydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boricacid, and partial salts of polybasic acids, e.g., KH₂PO₄, NaHSO₄; groupIa or IIa metal hydroxides such as sodium hydroxide, and potassiumhydroxide; ammonia; oxidizing agents such as hydrogen peroxide, benzoylperoxide, ammonium persulfate, potassium permanganate, hypochloricsalts, and the like; and mixtures thereof. It is particularlyadvantageous to use the butanedioic acid reactant in combination withhydrogen peroxide and metal catalyst to reduce the starch molecularweight which can then be made into ethersuccinylated starch hydroxylpolymer by adding the cation catalyst and alkalinity. In one example,the molecular weight of the ethersuccinylated starch hydroxyl polymermay be reduced by adding peroxide into the reaction mixture andincreasing the temperature at which the reaction mixture is subjected.

“Modified starch” is a starch that has been modified chemically orenzymatically. The modified starch is contrasted with a native starch,which is a starch that has not been modified, chemically or otherwise,in any way.

Chemical modifications may also include derivatization of starch byreaction of its hydroxyl groups with alkylene oxides, and other ether-,ester-, urethane-, carbamate-, or isocyanate-forming substances.Hydroxyalkyl, acetyl, or carbamate starches or mixtures thereof can beused as chemically modified starches. The degree of substitution of thechemically modified starch is from 0.05 to 3.0, and more specificallyfrom 0.05 to 0.2. If the derivatives are sensitive to alkalineconditions, for example esters, then such derivatization must be carriedout after the ethersuccinylation reaction. Biological modifications ofstarch may include bacterial digestion of the carbohydrate bonds, orenzymatic hydrolysis using enzymes such as amylase, amylopectase, andthe like.

Generally, all kinds of natural starches can be used in the presentinvention. Suitable naturally occurring starches can include, but arenot limited to: corn starch, potato starch, sweet potato starch, wheatstarch, sago palm starch, tapioca starch, rice starch, soybean starch,arrow root starch, amioca starch, bracken starch, lotus starch, waxymaize starch, and high amylose corn starch. Naturally occurringstarches, particularly corn starch and wheat starch, can be particularlybeneficial due to their low cost and availability.

In order to generate the required rheological properties for high-speedspinning processes, the molecular weight of the natural, unmodifiedstarch should be reduced. The optimum molecular weight is dependent onthe type of starch used. For example, a starch with a low level ofamylose component, such as a waxy maize starch, disperses rather easilyin an aqueous solution with the application of heat and does notretrograde or recrystallize significantly. With these properties, a waxymaize starch can be used at a relatively high weight average molecularweight, for example in the range of 500,000 g/mol to 5,000,000 g/mol.Modified starches such as ethersuccinylated Dent corn starch, whichcontains about 25% amylose, or oxidized Dent corn starch tend toretrograde more than waxy maize starch but less than acid thinnedstarch. This retrogradation, or recrystallization, acts as a physicalcross-linking to effectively raise the weight average molecular weightof the starch in aqueous solution. Therefore, an appropriate weightaverage molecular weight for a typical commercially availableethersuccinylated Dent corn starch with DS_(E)=0.026 is from about200,000 g/mol to about 3,000,000 g/mol. For ethersuccinylated starchhydroxyl polymers with higher degrees of ethersuccinylation, for examplea ethersuccinylated Dent corn starch with DS_(E)=0.083, weight averagemolecular weights of up to 40,000,000 g/mol may be suitable for thepresent invention.

The weight average molecular weight of starch can be reduced to thedesirable range for the present invention by chain scission (oxidativeor enzymatic), hydrolysis (acid or alkaline catalyzed),physical/mechanical degradation (e.g., via the thermomechanical energyinput of the processing equipment), or combinations thereof. Thethermo-mechanical method and the oxidation method offer an additionaladvantage in that they are capable of being carried out in situ duringthe polymer processing operation.

The natural starch can be hydrolyzed in the presence of an acid catalystto reduce the molecular weight and molecular weight distribution of thecomposition. The acid catalyst can be selected from the group consistingof hydrochloric acid, sulfuric acid, phosphoric acid, citric acid,butanedioic acid, and any combination thereof. Alternatively, a chainscission agent may be reacted with a starch slurry in the presence of ametal catalyst. Especially useful is the copper-catalyzed hydrogenperoxide scissions of starch as outlined in U.S. Pat. No. 3,655,644,U.S. Pat. No. 6,670,470 and WO03/097701 because the scission occursunder alkaline conditions as does the ethersuccinylation reaction andbecause the molecular weight can be controlled by the amount of hydrogenperoxide added. Also, a chain scission agent may be incorporated into aspinnable starch composition such that the chain scission reaction takesplace substantially concurrently with the blending of the starch withother components. Non-limiting examples of oxidative chain scissionagents suitable for use herein include ammonium persulfate, hydrogenperoxide, hypochlorite salts, potassium permanganate, and mixturesthereof. Typically, the chain scission agent is added in an amounteffective to reduce the weight average molecular weight of the starch tothe desirable range. It is found that compositions having modifiedstarches in the suitable weight average molecular weight ranges havesuitable shear viscosities, and thus improve processability of thecomposition. The improved processability is evident in lessinterruptions of the process (e.g., reduced breakage, shots, defects,hang-ups) and better surface appearance and strength properties of thefinal product, such as fibers of the present invention.

B. Cellulose Hydroxyl Polymers

Cellulose and modified cellulose-based polymer and/or oligomermaterials, (represented by Structure III below which are suitable foruse as the hydroxyl polymers of the present invention can becharacterized by the following general structures, alone or incombination:

wherein each R is selected from the group consisting of R_(a), R_(c),and R_(p),wherein:

each R_(a) is independently selected from the group consisting of H andC₁-C₄ alkyl;

each R_(c) is

-   -   wherein M is a suitable cation selected from the group        consisting of H⁺, Na⁺, K⁺, 1/2Ca²⁺, 1/2Mg²⁺, barium, zinc and        lanthanum (III), or ⁺NH_(j)R_(k) wherein j and k are        independently from 0 to 4 and wherein j+k is 4 and R in this        formula is any moiety capable of forming a cation, such as        methyl and/or ethyl group or derivative;

each R_(p) is

each R_(H) is independently selected from the group consisting of R_(a)and R_(c)

each x is from 1 to about 5;

n is a number that results in the polymer having a weight averagemolecular weight in accordance with the present invention.

In one example, the precursor cellulose hydroxyl polymer isunsubstituted and thus R equals H in Structure III. After theethersuccinylation reaction is carried out R is selected from the groupconsisting of R_(a), R_(c), R_(p), and R_(E);

wherein:

each ethersuccinate R_(E) is

and

each R_(H) is independently selected from the group consisting of R_(a),R_(c), and R_(E).

The “Degree of Substitution” for group R_(E), which is sometimesabbreviated herein “DS_(E)”, means the number of moles of group R_(E)components that are substituted per anhydrous glucose unit, wherein ananhydrous glucose unit is a six membered ring as shown in the repeatingunit of the general structure above.

The “Degree of Substitution” for group R_(C), which is sometimesabbreviated herein “DS_(C)”, means the number of moles of group R_(C)components, that are substituted per anhydrous D-glucose unit, whereinan anhydrous D-glucose unit is a six membered ring as shown in therepeating unit of the general structures above.C. Other Polysaccharide Hydroxyl Polymers

“Polysaccharides” herein means natural polysaccharides andpolysaccharide derivatives or modified polysaccharides. Suitable otherpolysaccharides include, but are not limited to, chitosan, chitosanderivatives, gums, arabinans, galactans and mixtures thereof.

The polysaccharides can be extracted from plants, produced by organisms,such as bacteria, fungi, prokaryotes, eukaryotes, extracted from animalsand/or humans. For example, xanthan gum can be produced by Xanthomonascampestris, gellan by Sphingomonas paucimobilis, xyloglucan can beextracted from tamarind seed.

The polysaccharides can be linear, or branched in a variety of ways,such as 1-2, 1-3, 1-4, 1-6, 2-3 and mixtures thereof.

It is desirable that the polysaccharides of the present invention have aweight average molecular weight in the range of from about 2,000 toabout 10,000,000, more and/or from about 500,000 to about 5,000,000,and/or from about 1,000,000 to about 5,000,000 g/mol.

In one example, the polysaccharide is selected from the group consistingof: tamarind gum (containing xyloglucan polymers), guar gum, chitosan,chitosan derivatives, locust bean gum (containing galactomannanpolymers), and other industrial gums and polymers, which include, butare not limited to, Tara, Fenugreek, Aloe, Chia, Flaxseed, Psylliumseed, quince seed, xanthan, gellan, welan, rhamsan, dextran, curdlan,pullulan, scleroglucan, schizophyllan, chitin, hydroxyalkyl cellulose,arabinan (such as from sugar beets), de-branched arabinan (such as fromsugar beets), arabinoxylan (such as from rye and wheat flour), galactan(such as from lupin and potatoes), pectic galactan (such as frompotatoes), galactomannan (such as from carob, and including both low andhigh viscosities), glucomannan, lichenan (such as from icelandic moss),mannan (such as from ivory nuts), pachyman, rhanmogalacturonan, acaciagum, agar, alginates, carrageenan, chitosan, clavan, hyaluronic acid,heparin, inulin, cellodextrins, and mixtures thereof. Thesepolysaccharides can also be treated (such as enzymatically) so that thebest fractions of the polysaccharides are isolated.

The natural polysaccharides can be modified with amines (primary,secondary, tertiary), amides, esters, ethers, alcohols, carboxylicacids, tosylates, sulfonates, sulfates, nitrates, phosphates andmixtures thereof. Such a modification can take place in position 2, 3and/or 6 of the glucose unit. If the derivatives are sensitive toalkaline conditions, for example esters, then such derivatization mustbe carried out after the ethersuccinylation reaction. Such modified orderivatized polysaccharides can be included in the compositions of thepresent invention in addition to the natural polysaccharides.

Nonlimiting examples of such modified polysaccharides include: carboxyland hydroxymethyl substitutions (e.g., glucuronic acid instead ofglucose); amino polysaccharides (amine substitution, e.g., glucosamineinstead of glucose); C₁-C₆ alkylated polysaccharides; acetylatedpolysaccharide ethers; polysaccharides having amino acid residuesattached (small fragments of glycoprotein); polysaccharides containingsilicone moieties. Suitable examples of such modified polysaccharidesare commercially available from Carbomer and include, but are notlimited to, amino alginates, such as hexanediamine alginate, aminefunctionalized cellulose-like O-methyl-(N-1,12-dodecanediamine)cellulose, biotin heparin, carboxymethylated dextran, guarpolycarboxylic acid, carboxymethylated locust bean gum,carboxymethylated xanthan, chitosan phosphate, chitosan phosphatesulfate, diethylaminoethyl dextran, dodecylamide alginate, and mixturesthereof.

The polysaccharide polymers can be linear, like inhydroxyalkylcellulose, the polymer can have an alternating repeat likein carrageenan, the polymer can have an interrupted repeat like inpectin, the polymer can be a block copolymer like in alginate, thepolymer can be branched like in dextran, the polymer can have a complexrepeat like in xanthan. Descriptions of the polymer definitions are givein “An introduction to Polysaccharide Biotechnology”, by M. Tombs and S.E. Harding, T. J. Press 1998.

D. Polyvinylalcohol Hydroxyl Polymers

Polyvinylalcohols which are suitable for use as the hydroxyl polymers(alone or in combination) of the present invention can be characterizedby the following general formula:

wherein each R is selected from the group consisting of R_(a), R_(c),and R_(p);wherein:

each R_(a) is independently selected from the group consisting of H andC₁-C₄ alkyl;

each R_(c) is

wherein M is a suitable cation selected from the group consisting of H⁺,Na⁺, K⁺, 1/2Ca²⁺, 1/2Mg²⁺, barium, zinc and lanthanum (III), or⁺NH_(j)R_(k) wherein j and k are independently from 0 to 4 and whereinj+k is 4 and R in this formula is any moiety capable of forming acation, such as methyl and/or ethyl group or derivative;

each R_(p) is

each R_(H) is independently selected from the group consisting of R_(a)and R_(c)

each x is from 1 to about 5;

each R_(D) is independently selected from H, R_(C) or CO₂M;

n is a number that results in the polymer having a weight averagemolecular weight in accordance with the present invention.

In one example, the precursor polyvinyl alcohol hydroxyl polymer isunsubstituted and thus R equals H in Structures IVa and IVb. After theethersuccinylation reaction is carried out R is selected from the groupconsisting of R_(a), R_(c), R_(p), and R_(E);

wherein:

each ethersuccinate R_(E) is

each R_(H) is independently selected from the group consisting of R_(a),R_(c), and R_(E).

The “Degree of Substitution” for group R_(E), which is sometimesabbreviated herein “DS_(E)”, means the number of moles of group R_(E)components that are substituted per total vinylalcohol units, whereinthe vinylalcohol unit is a the u unit as shown in the repeating unit ofthe general structure above.

Polymer Solution

The polymer solution may have a temperature of from about 50° C. toabout 100° C. and/or from about 65° C. to about 95° C. and/or from about70° C. to about 90° C. when making fibers from the polymer solution. Thepolymer solution temperature is generally higher when making film and/orfoam polymer structures, as described below.

The pH of the polymer solution may be from about 2.5 to about 9 and/orfrom about 3 to about 8.5 and/or from about 3.2 to about 8 and/or fromabout 3.2 to about 7.5.

The polymer solution may exhibit a Capillary Number of at least 1 and/orat least 3 and/or at least 5 such that the polymer solution can beeffectively polymer processed into a polymer structure, such as a fiber.In one example, the polymer solution exhibits a Capillary Number of fromat least 1 to about 50 and/or at least 3 to about 50 and/or at least 5to about 30. Further, the polymer solution may exhibit a pH of from atleast about 4 to about 12 and/or from at least about 4.5 to about 11.5and/or from at least about 4.5 to about 11.

A crosslinking system may be present in the polymer solution and/or maybe added to the polymer solution before polymer processing of thepolymer solution. Further, a crosslinking system may be added to thepolymer structure after polymer processing the polymer solution.

The crosslinking system of the present invention may further comprise,in addition to the crosslinking agent, a crosslinking facilitator.

“Crosslinking agent” as used herein means any material that is capableof crosslinking a hydroxyl polymer within a polymer solution accordingto the present.

Nonlimiting examples of suitable crosslinking agents includepolycarboxylic acids, imidazolidinones and other compounds resultingfrom alkyl substituted or unsubstituted cyclic adducts of glyoxal withureas, thioureas, guanidines, methylene diamides, and methylenedicarbamates and derivatives thereof; and mixtures thereof.

“Crosslinking facilitator” as used herein means any material that iscapable of activating a crosslinking agent thereby transforming thecrosslinking agent from its unactivated state to its activated state.

Upon crosslinking the hydroxyl polymer, the crosslinking agent becomesan integral part of the polymer structure as a result of crosslinkingthe hydroxyl polymer as shown in the following schematic representation:Hydroxyl polymer—Crosslinking agent—Hydroxyl polymer

The crosslinking facilitator may include derivatives of the materialthat may exist after the transformation/activation of the crosslinkingagent. For example, a crosslinking facilitator salt being chemicallychanged to its acid form and vice versa.

Nonlimiting examples of suitable crosslinking facilitators include acidshaving a pKa of between 2 and 6 or salts thereof. The crosslinkingfacilitators may be Bronsted Acids and/or salts thereof, such asammonium salts thereof.

In addition, metal salts, such as magnesium and zinc salts, can be usedalone or in combination with Bronsted Acids and/or salts thereof, ascrosslinking facilitators.

Nonlimiting examples of suitable crosslinking facilitators includeacetic acid, benzoic acid, citric acid, formic acid, glycolic acid,lactic acid, maleic acid, phthalic acid, phosphoric acid, succinic acidand mixtures thereof and/or their salts, such as their ammonium salts,such as ammonium glycolate, ammonium citrate, ammonium chloride andammonium sulfate.

Additional nonlimiting examples of suitable crosslinking facilitatorsinclude glyoxal bisulfite salts, primary amine salts, such ashydroxyethyl ammonium salts, hydroxypropyl ammonium salt, secondaryamine salts, ammonium toluene sulfonate, ammonium benzene sulfonate andammonium xylene sulfonate.

In another embodiment, the crosslinking system of the present inventionmay be applied to a pre-existing form as a coating and/or surfacetreatment.

The polymer solution may comprise a) from about 5% and/or 10% and/or 20%and/or 30% and/or 40% and/or 45% and/or 50% to about 75% and/or 80%and/or 85% and/or 90% and/or 99.5% by weight of the polymer solution ofone or more ethersuccinylated hydroxyl polymers; b) a crosslinkingsystem comprising from about 0.1% to about 10% by weight of the polymersolution of a crosslinking agent; and c) from about 0% and/or 10% and/or15% and/or 20% to about 50% and/or 55% and/or 60% and/or 70% by weightof the polymer solution of an external plasticizer e.g., water.

In one example, the polymer solution may comprise two or more differentclasses of hydroxyl polymers at weight ratios of from about 20:1 and/orfrom about 15:1 and/or from about 10:1 and/or from about 5:1 and/or fromabout 2:1 and/or from about 1:1 to about 1:20 and/or to about 1:15and/or to about 1:10 and/or to about 1:5 and/or to about 1:2 and/or toabout 1:1.

In another example, the polymer solution comprises from about 0.01% toabout 20% and/or from about 0.1% to about 15% and/or from about 1% toabout 12% and/or from about 2% to about 10% by weight of a first classof hydroxyl polymer, such as a polyvinyl alcohol hydroxyl polymer andfrom about 20% to about 99.99% and/or from about 25% to about 95% and/orfrom about 30% to about 90% and/or from about 40% to about 70% by weightof a second class of hydroxyl polymer, such as an ethersuccinylatedstarch hydroxyl polymer.

Nonlimiting Process for Making Ethersuccinylated Hydroxyl Polymer

A nonlimiting process for making ethersuccinylated hydroxyl polymers ofthe present invention is set forth below. Even though the followingnonlimiting example utilizes starch hydroxyl polymer, those of ordinaryskill in the art appreciate that other hydroxyl polymers can beethersuccinylated in the same or similar manner.

In one example, such a process is a high yield process when starch isthe precursor hydroxyl polymer. Yields of 70% or greater in one step arethe norm when starch is the hydroxyl polymer. (Yields herein are basedon the mol percentage of an α, β-unsaturated dicarboxylic acid or salts,such as maleic acid (a butenedioic acid), feedstock that are convertedto ethersuccinate substituents.) The making process can include recycleswhich can increase the yields further. Maximizing the yield is not theonly consideration herein. The invention also provides selections ofreaction conditions and compositions which provides theethersuccinylated starch hydroxyl polymer as an aqueous melt or aneasily handled granular solid. A further aspect of the process is thatit provides the ethersuccinylated hydroxyl polymer with the carboxylgroups in the acid form or coordinated to a cation or present with solidcalcium carbonate. A further aspect of the process is that native starchcan have its molecular weight reduced with α, β-unsaturated dicarboxylicacid or salts, hydrogen peroxide, and metal catalyst and then withoutisolation be submitted to the ethersuccinylation reaction.Alternatively, the ethersuccinylated hydroxyl polymer can have itsmolecular weight reduced with hydrogen peroxide under alkalineconditions.

In one example of a process for making an ethersuccinylated polymer inaccordance with the present invention, the components of the reactioncomposition are comprise a precursor hydroxyl polymer, an α,β-unsaturated dicarboxylic acid or salts, a cation catalyst and excessbase.

A. Reactor Design and Operating Pressures

The ethersuccinylation process of the invention has no pressurecriticality. However, since some hydroxyl polymers, for examplepolyvinylalcohol, are more difficult to deprotonate than starch, it canbe advantageous to heat the reaction mixture at temperatures abovereflux. A sealed reaction vessel of conventional construction, such as316 SS (stainless steel) is suitable. This reaction vessel need not beof titanium, nor need it be capable of withstanding high pressures,since the process is not corrosive and operates at low pressures ofabout 30 psi. As the aqueous polymer melt composition can be viscous, ascraped wall reactor is preferred. Alternatively, a screw extruder canbe used which is described below. When the ethersuccinylation reactionis performed on hydroxyl polymers which form very viscous aqueous melts,for example guar, it is preferable that the reaction not be carried outin a melt state but instead as a damp flour mixture in a double Z-bladejacketed reactor. When the ethersuccinylation reaction is carried out onstarch granules, a simple, stirred reaction tank can be used which canoptionally be blanketed with nitrogen to prevent the calcium hydroxidereacting with carbon dioxide in the air.

B. Reaction Temperatures and Times

Reaction temperatures for ethersuccinylation depend on whether thehydroxyl polymer is an aqueous polymer melt, damp flour or a granule. Inthe first case, the melt temperatures are above 80° C. and/or are in therange of about 105 to about 150° C. In the second and third case, thetemperatures are from about 40 to about 60° C. and/or from about 50 toabout 55° C. Under such temperatures, the granules tend to notgelatinize.

Reaction time for reactions carried out in batches is generally measuredas of completion of loading of all the components of the ethersuccinatereaction into the reactor and bringing the mixture as rapidly aspossible to the reaction temperature. Batch reaction times are fromabout 2-24 hr. Reaction time for reactions carried out in extruders orstatic mixers is generally measured as the residence time in the reactorand this varies from about 2 to about 10 min. Naturally, it will beappreciated that shorter reaction times may be accompanied by selectionof higher reaction temperatures within the indicated ranges.

C. Components of the Ethersuccinylation Reaction Mixture

The components herein are the hydroxyl polymer (as described above), anα,β-unsaturated dicarboxylic acid or salts, a cation catalyst, excessbase, and water. The α, β-unsaturated dicarboxylic acid or salts may bein organic acid form and both the cation catalyst and excess base canconveniently be provided simultaneously, for example as calciumhydroxide. Alternatively, it is possible to adjust the amounts of eachof the components independently.

In general, the molar ratio of the α, β-unsaturated dicarboxylic acid orsalts component to the hydroxyl polymer depends on the propertiesdesired from the ethersuccinylated hydroxyl polymer. For example, ifviscosity modification can be achieved with a low DS_(E) of 0.03, thenthe ratio of α, β-unsaturated dicarboxylic acid or salts component tohydroxyl polymer to form that particular DS_(E) would need to besomewhat higher than 0.03 depending on the yield. If the property ofcation binding requires a higher DS_(E), for example 0.6, then the ratioof α, β-unsaturated dicarboxylic acid or salts component to hydroxylpolymer would need to be between 0.66 and 1.2.

In general, the molar ratio of the cation catalyst to the α,β-unsaturated dicarboxylic acid or salts component is at least 0.5and/or greater than 1.0 and/or greater than 2.0 and/or between about 2.0to about 2.4.

In general, the molar ratio of excess base to the α, β-unsaturateddicarboxylic acid or salts component is at least 0.7 and/or greater than1.0 and/or greater than 1.5 and/or between about 1.5 to about 2.7.

In general, water is from about 30 to about 90 wt. % and/or from about55 to about 65 wt % of the reaction mixture.

D. Chemical and Physical Forms of the Reaction Components

The suitable hydroxyl polymers are described in the “Constitution ofHydroxyl Polymers”. The list of useful α, β-unsaturated dicarboxylicacid or salts reactants includes maleic anhydride (preferred), maleicacid, citraconic anhydride, citraconic acid, itaconic anhydride, anditaconic acid. The list of cation catalysts include calcium (preferred),magnesium, barium, zinc and lanthanum (III). In general, the chemicalform of the cation catalysts will be that of oxide or hydroxide such ascalcium oxide, calcium hydroxide, magnesium oxide, magnesium hydroxideor the like, or inert anion salts. The cation catalyst may be present inthe butanedioic acid reactant, for example, in the production ofitaconic and citraconic acid via fermentation each material is isolatedfrom the broth as a calcium salt and that salt could be used directly inthe ethersuccinylation process. For purposes of neutralizing the α,β-unsaturated dicarboxylic acid or salts reactant, salts such as calciumcarbonate may be used. The excess base may be provided by the cationcatalyst or by alkali hydroxides such as sodium hydroxide or potassiumhydroxide. Inert anions, for example sulfate, can optionally be presentherein. In one example, inert anions are not used in the processes ofthe invention. Process aids for example surfactants and hydrotropes canoptionally be used in the processes of the invention.

E. Recycling of Reaction Components

Ethersuccinylation of starch in the granular state provides anopportunity to recycle the α, β-unsaturated dicarboxylic acid or saltscomponent and the cation catalyst. Since calcium maleate is soluble upto 3.21 g per 100 mL of water at 40 C, the granules can be separated bycentrifugation or filtration. The calcium maleate remains in thesupernatant which can be used in a subsequent reaction. The amount of α,β-unsaturated dicarboxylic acid or salts reactant which is converted toethersuccinate substitutent in the reaction could be added to thereaction mixture, thus forming calcium maleate allowing furtherrecycling of calcium. Alternatively, the reaction mixture can beacidified with hydrochloric or acetic acid and the granules separated bycentrifugation or filtration. Maleic acid and either calcium chloride orcalcium acetate remain in the supernatant which can be used in asubsequent reaction. The ethersuccinylated hydroxyl polymer is alsoconverted to the acid form in this way.

In one example the ratio of the mmoles of excess cation catalyst, suchas calcium hydroxide, (as determined by subtracting the mmoles of α,β-unsaturated dicarboxylic acid or salts from the mmoles of the cationcatalyst), per gram of hydroxyl polymer, such as starch hydroxylpolymer, is 0.3 mmol/g or greater. (If the cation catalyst only has onehydroxide moiety associated with it, then the ratio values will bedoubled.) In another example, the ratio of the mmoles of excess cationcatalyst, such as calcium hydroxide, (as determined by subtracting themmoles of α, β-unsaturated dicarboxylic acid or salts from the mmoles ofthe cation catalyst), per gram of hydroxyl polymer, such as starchhydroxyl polymer, is from about 0.3 to about 0.7 mmol/g. In anotherexample, the ratio of the moles of cation catalyst, such as calciumhydroxide, to the moles of α, β-unsaturated dicarboxylic acid or saltsis greater than about 1.50. Under these examples, the need foradditional acid over and above the α, β-unsaturated dicarboxylic acid orsalts for this recycling operation to occur is limited or nonexistent.

F. Conversion of the Cation Catalyst to the Carbonate Form

In some applications it is desirable to minimize the salt content of theethersuccinylated hydroxyl polymer. This can achieved by washing thegranular product with acid as mentioned above or by converting thecation catalyst to an insoluble form, for example, carbonate. Carbondioxide can be bubbled through the reaction mixture or alternativelysodium, potassium or ammonium carbonate can be added to the reactionmixture. For some applications the carbonate particles should be lessthan 1 micron, for example in a thermoplastic melt for use in spinningfibers. Bubbling carbon dioxide through the reaction in the presence ofcrystal growth inhibitors like polyacrylates or aminophosphonates canprovide such small particles. After passing carbon dioxide through themixture, the pH can be adjusted to greater than 8 to about 14 and/orgreater than 8 to about 12 and/or greater than 8 to about 10 and/or fromabout 8.5 to about 9.5 to facilitate polymer solution formation.

In other applications it is desirable to remove the calcium ionaltogether from the ethersuccinylated hydroxyl polymer. In the case ofethersuccinylated starch in the granular form, this can be achieved byadding a source of carbonate ion such as sodium carbonate and keepingthe pH preferably between 10 and 10.5. The calcium carbonate formedunder these conditions has a larger particle size and can be more easilyseparated from granular ethersuccinylated starch with a hydrocyclone.

NONLIMITING SYNTHESIS EXAMPLES Example 1 Synthesis of Acid-ThinnedGranular Starch Ethersuccinate

Eclipse G starch (acid thinned corn starch from AE Staley) (280.00 g,1.73 mol) is placed in a 1000 mL bottle with lid along with 400 mLwater. Then calcium hydroxide (32.00 g, 0.43 mol) and maleic acid (21.00g, 0.18 mol) are added. The bottle is capped and placed in an 55° C.oven for 7 hr. The reaction mixture is then filtered and the precipitateis dried at 55° C. for 16 hr to give the product as white solid (310.55g). When observed under cross polars with a microscope, the solidconsists of birefringent starch granules. The acid content is determinedto be 0.81 mmol H/g, the degree of substitution is 0.069, and the yieldis 75% via Test Method A described herein.

Example 2 Synthesis of High Amylose Granular Starch Ethersuccinate

Hylon VII starch (high amylose corn starch from National Starch) (14.00g, 0.086 mol) is placed in a 100 mL bottle with lid along with 20 mLwater. Then calcium hydroxide (0.38 g, 5.13 mmol) and maleic acid (0.25g, 2.15 mmol) are added. The bottle is capped and placed in an 55° C.oven for 16 hr. The reaction mixture is then filtered, washed with water(3×20 mL), washed with methanol (1×40 mL), and the precipitate is driedat 55° C. for 4 hr to give the product as white solid (12.47 g). Whenobserved under cross polars with a microscope, the solid consists ofbirefringent starch granules. The acid content is determined to be 0.27mmol H/g, the degree of substitution is 0.022, and the yield is 88% viaTest Method A described herein.

Example 3 Synthesis of Acid-Thinned Destructured Starch Ethersuccinate

Eclipse G starch (105.00 g, 0.65 mol) is placed in a 1000 mL stainlesssteel beaker along with 400 mL water. Then calcium hydroxide (15.00 g,0.20 mol) is added. The reaction mixture is placed in a hot water bathheld at 70° C. and stirred with a Jiffy mixer. Then maleic acid (7.87 g,0.068 mol) is added. The reaction mixture formed a light yellow gel andduring the course of the reaction additional water is added to keep thegel fluid. After 3 hr of heating the reaction is terminated and themixture weighed 706.41 g. A 46.00 gram portion of the reaction mixtureis converted to 4.78 g of the acid form. The acid content is determinedto be 0.74 mmol H/g, the degree of substitution is 0.063, and the yieldis 62% via Test Method A described herein.

Example 4 Synthesis Via Extruder of Acid-Thinned Destructured StarchEthersuccinate

Water (10000 g) is added to a Ekato/Unimix conical, 35 L, scraped wall,jacketed mixing tank with pressure capability. Then Eclipse G starch(6000 g) and calcium hydroxide (1984 g) is dispersed in 2000 g water toform a calcium hydroxide/starch mixture. The mixture is stirred andheated at 110° C. for 3 hr. The majority of the starch granules arebirefringent.

The calcium hydroxide/starch mixture is added via a Zenith B9000 gearpump (4.5 cc/revolution) to port 2 of an APV 40:1 50 mm corotating twinscrew extruder as described herein below. A 34.2% maleic acid solutionis added to port 3 via PREP 100 HPLC pump (Chrom Tech, Apple ValleyMinn.). Ammonium chloride (25% w/w) is added to the static mixer tobring the pH between 8 and 9.5. Water is also added to the static mixerto adjust the melt viscosity. The reactants are added with the followingfeed rates:

Maleic Water NH₄Cl Ca(OH)₂/ Water acid at Static at Static Starch starchslurry at Port 2 (34.2%) Mixer Mixer (g/min) (g/min) (g/min) (g/min)(g/min) (g/min) 241 243.3 61 48 1.6 24.8Samples are taken at the dump after the static mixer for analysis. Theacid content is determined to be 0.35 mmol H/g, the degree ofsubstitution is 0.029, and the yield is 38% via Test Method A describedherein. The viscosity is 7.8231 Pa s at a shear rate of 3000 s⁻¹ and then value is 0.54. The water content was 45.29% and using method G, the pHis 9.22.

Example 5 Synthesis of Native Corn Starch Ethersuccinate

Native corn starch (140.00 g, 0.86 mol), calcium hydroxide (10.82 g,0.146 mol), maleic acid (10.50 g, 0.0905 mol) and water (214 mL) arecharged to a jacketed 1 L reactor fitted with a recirculation bath,mechanical stirrer, pH probe, and combination gas inlet/syringe portadapter. The reaction mixture is kept at 50° C. under argon for 19hours. A 13.48 g aliquot of the reaction mixture is converted to 4.10 gof the acid form. The acid content is determined to be 0.75 mmol H/g,the degree of substitution is 0.063 and the yield is 63% via Test MethodA described below. The mmoles of excess calcium hydroxide per gram ofstarch is (146 mmoles−90.5 mmoles)/140 g=0.4 mmoles/g. The mmoles ofmaleic acid attached to the starch is (0.63×90.5 mmoles)/140 g=0.41mmoles/g.

Example 6 Synthesis of Native Corn Starch Ethersuccinate

Native corn starch (140.00 g, 0.86 mol), calcium hydroxide (17.99 g,0.242 mol), maleic acid (17.29 g, 0.149 mol) and water (400 mL) arecharged to a jacketed 1 L reactor fitted with a recirculation bath,mechanical stirrer, pH probe, and combination gas inlet/syringe portadapter. The reaction mixture is kept at 50° C. under argon for 20 hoursand then filtered by suction filtration to give 352.78 g of wet cake. A122.78 g aliquot of the wet cake is suspended in 300 mL of 2:1 v/vMeOH/water containing 30 mL of concentrated hydrochloric acid. Thesuspension is filtered and the precipitate washed with 700 mL of 2:1 v/vMeOH/water until the filtrate is pH 5. The precipitate is washed with200 mL of MeOH and dried at 65 C in an oven for 1 hr to give 42.62 g ofwhite product. The acid content is determined to be 1.36 mmol H/g, thedegree of substitution is 0.12 and the yield is 69% via Test Method Adescribed below. The mmoles of excess calcium hydroxide per gram ofstarch is (242 mmoles−149 mmoles)/140 g=0.66 mmoles/g. The mmoles ofmaleic acid attached to the starch is (0.69×149 mmoles)/140 g=0.73mmoles/g. The HNMR spectrum shows a broad resonance at 2.8 ppm for themethylene protons of the ethersuccinate group. The degree ofsubstitution can also be determined by dividing by two the integrationratio of the 2.8 ppm resonance to the anomeric glucoside protonresonances at 5.3 and 5.7 ppm. By this method the degree of substitutionis 0.14.

Example 7 Synthesis of Peroxide-Thinned Granular Starch Ethersuccinate

Native corn starch (140.00 g, 0.86 mol), 1% aqueous copper sulfatepentahydrate (1.40 mL, 5.61 mmol), and water (400 mL) are charged to ajacketed 1 L reactor fitted with a recirculation bath, mechanicalstirrer, pH probe, and combination gas inlet/syringe port adapter. Thereaction mixture was adjusted to pH 9.2 with 1 N sodium hydroxide. Then30% hydrogen peroxide (11.84 g, 0.10 mol) was added dropwise over 30 minusing a syringe pump. The reaction mixture is kept at 40 C for 95 minuntil the peroxide content is <10 ppm as determined by peroxide teststrips. Then calcium hydroxide (10.82 g, 0.148 mol) and maleic acid(10.50 g, 0.0905 mol) are charged to the reactor. The reaction mixtureis kept at 50° C. under argon for 20 hours. A 10 mL aliquot of thereaction mixture was withdrawn and submitted to Test Method A describedherein. The acid content is determined to be 0.80 mmol H/g, the degreeof substitution is 0.068 and the yield is 68% via Test Method Adescribed below.

Example 8 Synthesis of Guar Ethersuccinate

Guar (purchased from Sigma) (14.00 g, 0.086 mol) and maleic acid (0.53g, 4.57 mmol) is placed in a mortar and pestle. Then calcium hydroxide(0.80 g, 10.8 mmol) dispersed in 14 g water is added. The reaction ismixed thoroughly and transferred to a 100 mL bottle with lid. The bottleis capped and placed in an 65° C. oven for 24 hr. The reaction mixtureis then converted to the acid form. The acid content is determined to be0.26 mmol H/g, the degree of substitution is 0.022, and the yield is 41%via Test Method A described herein.

Example 9 Synthesis of Cellulose Ethersuccinate

Eucalyptus pulp (5.00 g, 0.0309 mol) is ground up in a coffee grinderand then maleic acid (0.58 g, 5.00 mmol) is added and mixed with thecoffee grinder. The mixture is transferred to a 100 mL bottle with lidand calcium hydroxide (0.86 g, 11.6 mmol) dispersed in 15 g water isadded. The bottle is capped and placed in an 65° C. oven for 24 hr. Thereaction mixture is then converted to the acid form. The acid content isdetermined to be 0.44 mmol H/g, the degree of substitution is 0.037, andthe yield is 23% via Test Method A described herein.

Example 10 Synthesis of Polyvinylalcohol Ethersuccinate

Polyvinylalcohol (Celvol 107, 98.4% hydrolyzed, Celanese) (28.00 g, 0.64mol) is placed in a 180 mL stainless steel beaker along with 90 mLwater. After stirring with a Jiffy mixer for 1 hr at 80° C., thepolyvinylalcohol is dissolved. Then calcium hydroxide (3.20 g, 0.043mol) suspended in 10 mL water is added, followed by maleic acid (2.10 g,0.017 mol). The reaction mixture is placed in a hot water bath held at80° C. for 2.5 hr. Reaction weight is 116.42 g. A 29.41 g portion of thereaction mixture is converted to 1.71 g of the acid form. The acidcontent is determined to be 0.48 mmol H/g, the degree of substitution is0.011, and the yield is 41% via Test Method A described herein.

Nonlimiting Example of a Process for Making a Hydroxyl Polymer Structure

Any suitable process known to those skilled in the art can be used toproduce the polymer solution and/or to polymer process the polymersolution and/or to produce the polymer structure of the presentinvention. Nonlimiting examples of such processes are described inpublished applications: EP 1 035 239, EP 1 132 427, EP 1 217 106, EP 1217 107, WO 03/066942 and U.S. Pat. No. 5,342,225.

a. Making a Polymer Solution

A polymer solution comprising an ethersuccinylated hydroxyl polymer ofthe present invention may be prepared using a screw extruder, such as avented twin screw extruder.

A barrel 10 of an APV Baker (Peterborough, England) twin screw extruderis schematically illustrated in FIG. 1A. The barrel 10 is separated intoeight zones, identified as zones 1-8. The barrel 10 encloses theextrusion screw and mixing elements, schematically shown in FIG. 1B, andserves as a containment vessel during the extrusion process. A solidfeed port 12 is disposed in zone 1 and a liquid feed port 14 is disposedin zone 1. A vent 16 is included in zone 7 for cooling and decreasingthe liquid, such as water, content of the mixture prior to exiting theextruder. An optional vent stuffer, commercially available from APVBaker, can be employed to prevent the polymer solution from exitingthrough the vent 16. The flow of the polymer solution through the barrel10 is from zone 1 exiting the barrel 10 at zone 8.

A screw and mixing element configuration for the twin screw extruder isschematically illustrated in FIG. 1B. The twin screw extruder comprisesa plurality of twin lead screws (TLS) (designated A and B) and singlelead screws (SLS) (designated C and D) installed in series. Screwelements (A-D) are characterized by the number of continuous leads andthe pitch of these leads.

A lead is a flight (at a given helix angle) that wraps the core of thescrew element. The number of leads indicates the number of flightswrapping the core at any given location along the length of the screw.Increasing the number of leads reduces the volumetric capacity of thescrew and increases the pressure generating capability of the screw.

The pitch of the screw is the distance needed for a flight to completeone revolution of the core. It is expressed as the number of screwelement diameters per one complete revolution of a flight. Decreasingthe pitch of the screw increases the pressure generated by the screw anddecreases the volumetric capacity of the screw.

The length of a screw element is reported as the ratio of length of theelement divided by the diameter of the element.

This example uses TLS and SLS. Screw element A is a TLS with a 1.0 pitchand a 1.5 length ratio. Screw element B is a TLS with a 1.0 pitch and a1.0 L/D ratio. Screw element C is a SLS with a ¼ pitch and a 1.0 lengthratio. Screw element D is a SLS and a ¼ pitch and a ½ length ratio.

Bilobal paddles, E, serving as mixing elements, are also included inseries with the SLS and TLS screw elements in order to enhance mixing.Various configurations of bilobal paddles and reversing elements F,single and twin lead screws threaded in the opposite direction, are usedin order to control flow and corresponding mixing time.

In zone 1, an ethersuccinylated hydroxyl polymer is fed into the solidfeed port at a rate of 183 grams/minute using a K-Tron (Pitman, N.J.)loss-in-weight feeder.

These the ethersuccinylated hydroxyl polymer is combined inside theextruder (zone 1) with the water, an external plasticizer, added at theliquid feed at a rate of 136 grams/minute using a Milton Roy (Ivyland,Pa.) diaphragm pump (1.9 gallon per hour pump head) to form a polymersolution. The polymer solution is then conveyed down the barrel of theextruder and cooked, in the presence of an alkaline agent, such asammonium hydroxide and/or sodium hydroxide. (introduction of externalplasticizer such as glycerin) The cooking causes a hydrogen from atleast one hydroxyl moiety on one or more of the hydroxyl polymers tobecome disassociated from the oxygen atom of the hydroxyl moiety andthus creates a negative charge on the oxygen atom of the former hydroxylmoiety. This oxygen atom is now open for substitution by a substitutionagent, such as a cationic agent, such as a quaternary ammonium compound,for example a quaternary amine.

Table 1 describes the temperature, pressure, and corresponding functionof each zone of the extruder.

TABLE 1 Temp. Description of Zone (° F.) Pressure Screw Purpose 1 70 LowFeeding/Conveying Feeding and Mixing 2 70 Low Conveying Mixing andConveying 3 70 Low Conveying Mixing and Conveying 4 130 LowPressure/Decreased Conveying and Heating Conveying 5 300 Medium PressureGenerating Cooking at Pressure and Temperature 6 250 High ReversingCooking at Pressure and Temperature 7 210 Low Conveying Cooling andConveying (with venting) 8 210 Low Pressure Generating ConveyingAfter the third hydroxyl polymer solution exits the extruder, part ofthe polymer solution can be dumped and another part (100 g) can be fedinto a Zenith®, type PEP II (Sanford N.C.) and pumped into a SMX stylestatic mixer (Koch-Glitsch, Woodridge, Ill.). The static mixer is usedto combine additional additives such as crosslinking agents,crosslinking facilitators, external plasticizers, such as water, withthe third hydroxyl polymer solution. The additives are pumped into thestatic mixer via PREP 100 HPLC pumps (Chrom Tech, Apple Valley Minn.).These pumps provide high pressure, low volume addition capability. Thethird hydroxyl polymer solution of the present invention exhibits aCapillary Number of at least 1 and thus, is ready to be polymerprocessed into a polymer structure.b. Polymer Processing the Polymer Solution into a Polymer Structure

The polymer processable hydroxyl polymer solution is then polymerprocessed into a hydroxyl polymer structure, such as a fiber.Nonlimiting examples of polymer processing operations include extrusion,molding and/or fiber spinning. Extrusion and molding (either casting orblown), typically produce films, sheets and various profile extrusions.Molding may include injection molding, blown molding and/or compressionmolding. Fiber spinning may include spun bonding, melt blowing,continuous fiber producing and/or tow fiber producing. Fiber spinningmay be dry spinning or wet spinning. Polymer structures produced as aresult of polymer processing of a polymer solution in accordance withthe present invention may be combined, such as when the polymerstructures are in the form of fibers, into a fibrous structure bycollecting a plurality of the fibers onto a belt or fabric.

A polymer structure and/or fibrous structure of the present inventionmay then be post-processed by subjecting the web to a post-processingoperation. Nonlimiting examples of post processing operations includecuring, embossing, thermal bonding, humidifying, perfing, calendering,printing, differential densifying, tuft deformation generation, andother known post-processing operations.

c. Post-Processing the Fibrous Structure

In one example, a fibrous structure formed by processing the polymersolution according to the present invention into a plurality of fibersis subjected to a post-processing operation.

The fibrous structure of the present invention may be cured during acuring operation by subjecting the fibrous structure to a temperature offrom about 110° C. to about 215° C. and/or from about 110° C. to about200° C. and/or from about 120° C. to about 195° C. and/or from about130° C. to about 185° C. for a time period of from about 0.01 and/or 1and/or 5 and/or 15 seconds to about 60 minutes and/or from about 20seconds to about 45 minutes and/or from about 30 seconds to about 30minutes. In one example, the curing operation comprises passing thefibrous structure over curing plates set at about 135° C. to about 155°C. Alternative curing operations include radiation methods such as UV,e-beam, IR and other temperature-raising methods.

Other Applications of Ethersuccinylated Hydroxyl Polymers

The ethersuccinylated hydroxyl polymers of the present invention mayexhibit properties related to viscosity modification, solubility, filmformation, polymer compatibilization, melt/solution processability,solid suspension, emulsion stabilization, cation binding, crystal growthinhibition, adhesiveness and swelling of crosslinked ethersuccinylatedhydroxyl polymers and/or as supersorbers.

Applications involving viscosity modification include thickeners to beused in foods, pharmaceuticals, latex paints, personal care products,and petroleum fracturing. For thickener applications, theethersuccinylated starch hydroxyl polymer may have a DS of 0.05-0.7 andhave a MW>500,000. Granular ethersuccinylated starch hydroxyl polymer inthe calcium form (obtained directly from the reaction) may beparticularly advantageous in that it retains its granular nature untilthe calcium is removed either by a sequestrant or acid and then itrapidly swells.

The swelling properties of ethersuccinylated starch hydroxyl polymerallow its use as a disintegrant in tablets. For disintegrantapplications, the ethersuccinylated starch hydroxyl polymer may have aDS of 0.05-0.5, and may be prepared from unmodified potato starch, M inStructure I above may be a mixture of H and Na, and theethersuccinylated starch hydroxyl polymer may be crosslinked.

For absorbent properties, the ethersuccinylated native corn starchhydroxyl polymer may have a DS of 0.12 and be crosslinked withcrosslinker at a molar ratio of crosslinker to glucoside units of 0.007.It may be advantageous to use ethersuccinylated native corn starchhydroxyl polymer with a DS of 0.12 in combination with guar.

As a textile sizing agent, an ethersuccinylated waxy corn starchhydroxyl polymer may be advantageous especially if applied withimidazole. The imidazole can catalyze esterification of cellulose withethersuccinylated starch during ironing and thus provide an anti-wrinklebenefit.

Ethersuccinylated starch hydroxyl polymer may also function inpapermaking as a wet and dry strength resin.

Applications involving its adhesiveness include adhesives, ceramics, drywall joint compounds, and binders for various products.

Emulsification properties of ethersuccinylated polyvinylalcohol could beused in emulsion polymerizations, emulsification in foods,pharmaceuticals and personal care products.

Applications of film forming properties include coatings, textile warpsizing and paper processing. The granular ethersuccinylated starchhydroxyl polymer with calcium carbonate may be particularly useful inmodifying paper properties such as opacity.

Applications involving solid suspension and crystal growth inhibitionproperties may be particularly suitable for detergent and ore processingapplications. For these applications the DS may range from about 0.1 toabout 0.7 and the MW from about 10,000 to about 100,000.

Applications of the ethersuccinylated hydroxyl polymers of the presentinvention include supersorbers for use in such products as diapersand/or training pants and/or feminine hygiene products and/or adultincontinence products.

Test Methods of the Present Invention

A. Determination of Acid Content, Degree of Ethersuccinate Substitution,and % Yield

A 10 g weighed sample of ethersuccinylated hydroxyl polymer was firstconverted to the acid form and unreacted maleic acid removed. Insolublematerials, for example low DS ethersuccinylated granular starch andcellulose, were suspended in 50 mL DI water containing 10 mL ofconcentrated hydrochloric acid. The starch or cellulose was collected bysuction filtration and washed with water (4×100 mL) until the filtratewas about pH 5. The starch or cellulose was washed with methanol (1×50mL) and dried at room temperature to a constant weight. Granularmaterials which gel in water, for example ethersuccinylated guar, wereconverted similarly except that 1:1 v/v MeOH/water was used in place ofwater. Materials which are already gelled, for example ethersuccinylateddestructured starch and polyvinylalcohol, were dissolved in 50 mL waterwith 10 mL concentrated hydrochloric acid added. Then methanol (100 mL)was added and the ethersuccinylated material precipitated with a woodpulp consistency. The precipitate was squeezed with a spatula to removethe supernatant. The precipitate was dissolved in 50 mL water, methanol(200 mL) added to precipitate the ethersuccinylated material, and theprecipitate squeezed with a spatula to remove the supernatant. Thisprocedure was repeated until the supernatant had a pH˜5 and then thesupernatant was allowed to dry at room temperature to a constant weight.

A 0.4-2 g weighed sample (depending on the DS of the ethersuccinylatedpolymer) of ethersuccinylated hydroxyl polymer in the acid form wasplaced in 50 mL 2.5% sodium chloride solution and heated to boiling toeffect dissolution. Then 0.1 N sodium hydroxide (20.0 mL) was added tothe solution or suspension which usually immediately became clear. Adrop of 0.5 wt % phenolphthalein solution was added and titration with0.1 N hydrochloric acid was performed.

${{Acid}\mspace{14mu}{content}} = {\frac{( {20\text{-}{mL}\mspace{20mu} 0.1\mspace{14mu}{HCl}} ) \times 0.1\mspace{14mu}{mmol}\text{/}{mL}}{{{Wt}.\mspace{14mu}(g)}\mspace{14mu}{sample}\mspace{14mu}{titrated}} = {{mmol}\mspace{14mu} H\text{/}g\mspace{14mu}{sample}}}$${{Degree}\mspace{14mu}{of}\mspace{14mu}{Substitution}\mspace{14mu}( {{for}\mspace{14mu}{polyglucosides}} )} = \frac{0.081 \times ( {{Acid}\mspace{14mu}{content}} )}{1 - \lbrack {(0.058) \times ( {{Acid}\mspace{14mu}{content}} )} \rbrack}$${{Theoretical}\mspace{14mu}{Degree}\mspace{14mu}{of}\mspace{14mu}{Substitution}} = \frac{{mols}\mspace{14mu}{maleic}\mspace{14mu}{acid}\mspace{14mu}{in}\mspace{14mu}{reaction}}{{mols}\mspace{14mu}{of}\mspace{14mu}{hydroxyl}\mspace{14mu}{monomer}\mspace{14mu}{units}\mspace{14mu}{in}\mspace{14mu}{reaction}}$%  Yield = Actual  Degree  of  Substitution/Theoretical  Degree  of  SubstitutionB. Fiber Diameter Test Method

A polymeric structure comprising fibers of appropriate basis weight(approximately 5 to 20 grams/square meter) is cut into a rectangularshape, approximately 20 mm by 35 mm. The sample is then coated using aSEM sputter coater (EMS Inc, PA, USA) with gold so as to make the fibersrelatively opaque. Typical coating thickness is between 50 and 250 nm.The sample is then mounted between two standard microscope slides andcompressed together using small binder clips. The sample is imaged usinga 10× objective on an Olympus BHS microscope with the microscopelight-collimating lens moved as far from the objective lens as possible.Images are captured using a Nikon D1 digital camera. A Glass microscopemicrometer is used to calibrate the spatial distances of the images. Theapproximate resolution of the images is 1 μm/pixel. Images willtypically show a distinct bimodal distribution in the intensityhistogram corresponding to the fibers and the background. Cameraadjustments or different basis weights are used to achieve an acceptablebimodal distribution. Typically 10 images per sample are taken and theimage analysis results averaged.

The images are analyzed in a similar manner to that described by B.Pourdeyhimi, R. and R. Dent in “Measuring fiber diameter distribution innonwovens” (Textile Res. J. 69(4) 233-236, 1999). Digital images areanalyzed by computer using the MATLAB (Version. 6.3) and the MATLABImage Processing Tool Box (Version 3.) The image is first converted intoa grayscale. The image is then binarized into black and white pixelsusing a threshold value that minimizes the intraclass variance of thethresholded black and white pixels. Once the image has been binarized,the image is skeltonized to locate the center of each fiber in theimage. The distance transform of the binarized image is also computed.The scalar product of the skeltonized image and the distance mapprovides an image whose pixel intensity is either zero or the radius ofthe fiber at that location. Pixels within one radius of the junctionbetween two overlapping fibers are not counted if the distance theyrepresent is smaller than the radius of the junction. The remainingpixels are then used to compute a length-weighted histogram of fiberdiameters contained in the image.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”.

While particular embodiments and/or individual features of the presentinvention have been illustrated and described, it would be obvious tothose skilled in the art that various other changes and modificationscan be made without departing from the spirit and scope of theinvention. Further, it should be apparent that all combinations of suchembodiments and features are possible and can result in preferredexecutions of the invention. Therefore, the appended claims are intendedto cover all such changes and modifications that are within the scope ofthis invention.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention.

1. A process for making a hydroxyl polymer wherein the process comprisesthe steps of: a. reacting a precursor hydroxyl polymer selected from thegroup consisting of: polyvinyl alcohol, polyvinyl alcohol derivatives,polyvinyl alcohol copolymers, starch, starch derivatives, chitosan,chitosan derivatives, cellulose, cellulose derivatives, gums, arabinans,galactans, proteins and mixtures thereof with an α, β-unsaturateddicarboxylic acid or salts thereof to produce a hydroxyl polymercomprising an ethersuccinate moiety having the formula:

wherein R¹, R² and R³ are independently selected from H, branched orlinear C₁-C₄ alkyl and mixtures thereof; R⁴ is (CH₂)_(y); M isindependently selected from H, cations and mixtures thereof; x isgreater than 0 but less than or equal to 1; y is 0 or 1, wherein theethersuccinate moiety is covalently bonded to a carbon atom in thehydroxyl polymer; and b. recycling the α, β-unsaturated dicarboxylicacid or salts thereof.
 2. The process according to claim 1 wherein theα, β-unsaturated dicarboxylic acid or salts thereof comprises an alkenedicarboxylic acid or salt thereof.
 3. The process according to claim 2wherein the alkene dicarboxylic acid is selected from the groupconsisting of: maleic acid, itaconic acid, citraconic acid and mixturesthereof.
 4. The process according to claim 1 wherein the step ofreacting occurs in the presence of an alkaline earth metal salt.
 5. Theprocess according to claim 4 wherein the alkaline earth metal saltcomprises Ca(OH)₂.
 6. The process according to claim 4 wherein the ratioof the mmoles of excess alkaline earth metal salt per gram of precursorhydroxyl polymer is 0.3 mmol/g or greater.
 7. The process according toclaim 6 wherein the ratio is from about 0.3 to about 0.7 mmol/g.